In recent years, portable electronic devices, such as mobile phones, portable cameras, notebook computers, digital cameras, personal digital assistants (PDAs), CD players, are becoming popular owing to their lightweight and small size. Batteries used as a portable power source have also become the focus of public concern, and have been an essential element of the various portable electronic devices.
Although some of common batteries, such as carbon-zinc batteries, alkaline batteries and secondary batteries, are allegedly environment-benign, they in fact largely contain substantial amounts of mercury and other heavy metals, such as cobalt. In addition, environmental pollutants are frequently used or released during battery manufacturing process.
Lithium batteries, though widely adopted as the largest energy content among the portable batteries, are unstable in the electrochemical reactions. In the worst scenario, explosions may occur due to its thermal runaway as the result of operating at low load or under improper assemblage. Therefore, multiple and complex protection mechanisms should be implemented for their usage, such as the installation of a protection circuit, an exhaust vent, and isolation membranes, etc.
The price of the lithium batteries rises rapidly as a result of the depletion of lithium mineral, which is the main raw material of the positive electrode (such as Li1-xCoO2) and the negative electrode (such as LixC) of lithium batteries. Furthermore, the performance and operating life of the lithium batteries decrease rapidly within a high temperature environment.
Therefore, an unaddressed need for a flat-plate battery using chlorophyll to generate electricity exists in the art to address the aforementioned deficiencies and inadequacies.